The invention relates, in general, to an apparatus and method for forming an occlusion in a mammalian body, and, in particular, to an apparatus and method for controlling a magnetically controllable substance in the embolization of an aneurysm.
Like all parts of the body, the brain is composed of living cells that require a blood supply to provide oxygen and nutrients. A hemorrhage in a blood vessel in the brain or in the space closely surrounding the brain is a common cause of strokes. Hemorrhage refers to bleeding into the brain, usually because of a problem with a blood vessel. The problem is often an aneurysm.
An aneurysm is an abnormal bulging outward of blood vessel wall. The wall may smoothly bulge outward in all directions (a fusiform aneurysm) or it may form a sack arising from one wall (a saccular aneurysm). If the aneurysm ruptures, a hemorrhage occurs. This can compress and irritate the surrounding blood vessels, resulting in a reduced supply of oxygen and nutrients to the cells, possibly causing a stroke.
Aneurysms can be treated from outside the blood vessel using surgical techniques or from inside the blood vessel using endovascular techniques. Endovascular treatment of an aneurysm is performed using a catheter. X-ray, magnetic resonance imaging (MRI) equipment, or other visualization equipment may be used to view the progress during the procedure.
A magnetically directable embolic such as an acrylic, iron-containing glue has been proposed to fill or obliterate aneurysms. The embolic is delivered by means of a catheter and is directed into an aneurysm with an external magnetic field generated by a permanent magnet or electrogmanetic device used for Stereotaxis prcedures such as a prototype device made by Steteotaxis Inc. of St. Louis, Mo. An example of such a device is shown and described in U.S. Pat. No. 6,014,580 to Blume, et al. Excess embolic delivered to the aneurysm could enter the bloodstream and cause serious complications downstream, e.g., stroke. The inventors of the present invention have recognized that a need exists to precisely control embolic delivery at the delivery end of the catheter to prevent excess embolic being delivered to the aneurysm.
An aspect of the present invention involves a magnetic embolization apparatus for embolizing an aneurysm of a blood vessel. The magnetic embolization apparatus includes a catheter having a distal portion adapted for insertion within an aneurysm of a blood vessel, a permanent magnet carried by the distal portion of the catheter to internally induce a magnetic field from within the aneurysm to control a magnetic field controllable embolic to embolize the aneurysm, and an electromagnet carried by the distal portion of the catheter to internally induce a magnetic field to control delivery of the magnetic field controllable embolic.
Implementations of the aspect of the invention described immediately above may include one or more of the following. The permanent magnet is located circumferentially outside or inside the electromagnet. A wall of the catheter includes the permanent magnet. The electromagnet is adapted to induce a magnetic field in a first direction to embolize the aneurysm and in a second direction to counteract the magnetic field of the permanent magnet.
An additional aspect of the invention includes a method of embolizing an aneurysm of a blood vessel. The method includes delivering a magnetic-field controllable embolic into an aneurysm, inducing a magnetic field in the aneurysm to control the magnetic-field controllable embolic to embolize the aneurysm, and controlling delivery of the magnetic-field controllable embolic into the aneurysm by actuating an electromagnet adjacent the aneurysm.
Implementations of the aspect of the invention described immediately above may include one or more of the following. A catheter includes a distal portion with a permanent magnet and the electromagnet located therein, and the permanent magnet is located circumferentially outside the electromagnet and is used to induce the magnetic field in the aneurysm. A catheter includes a distal portion with a permanent magnet and the electromagnet located therein, and the permanent magnet is located circumferentially inside the electromagnet and is used to induce the magnetic field in the aneurysm. A catheter includes a wall with a permanent magnet located therein and the permanent magnet is used to induce the magnetic field in the aneurysm.
The method further includes strengthening the magnetic field induced by the permanent magnet to embolize the aneurysm by actuating the electromagnet, and stopping the delivery of the magnetic-field controllable embolic by reversing polarity in the electromagnet to produce a magnetic field that counteracts the magnetic field of the permanent magnet.
A further aspect of the invention involves a method of embolizing an aneurysm of a blood vessel. The method includes delivering a magnetic-field controllable embolic into an aneurysm with a lumen of a catheter, internally inducing a magnetic field from within the aneurysm to control the magnetic-field controllable embolic to embolize the aneurysm with a permanent magnet of the catheter, and counteracting the magnetic field induced by the permanent magnet with a magnetic field induced by an electromagnet to remove the catheter from the aneurysm without removing the embolic.
Implementations of the aspect of the invention described immediately above may include one or more of the following. The catheter is a dual-lumen catheter having a first lumen and a second lumen, a guide wire is slidably disposed in the first lumen and carries the permanent magnet, the second lumen is adapted to deliver the magnetic field controllable embolic, and the method further includes delivering the magnetic field controllable embolic into the aneurysm through the second lumen and introducing the permanent magnet of the guide wire into the aneurysm to internally induce the magnetic field from within the aneurysm to control the magnetic-field controllable embolic to embolize the aneurysm. The first lumen is defined by a first lumen wall, and the electromagnet is located in the first lumen wall. The catheter is a dual-lumen catheter having a first lumen and a second lumen, the first lumen carries the permanent magnet, the second lumen is adapted to deliver the magnetic field controllable embolic, and the method further includes delivering the magnetic field controllable embolic into the aneurysm through the second lumen.
An additional aspect of the invention involves a magnetic embolization apparatus for embolizing an aneurysm of a blood vessel. The apparatus includes a catheter having a distal portion, a detachable permanent magnetic element and pusher wire carried by the catheter, and an electromagnet carried by the distal portion of the catheter to induce a magnetic field for controlling delivery of the magnetic field controllable embolic.
A further aspect of the invention involves a method of embolizing an aneurysm of a blood vessel. The method includes deploying a detachable permanent magnetic element into the aneurysm; delivering a magnetic-field controllable embolic into the aneurysm so that the detachable permanent magnetic element draws the magnetic-field controllable embolic into the aneurysm to embolize the aneurysm; and controlling delivery of the magnetic-field controllable embolic with an electromagnet.
Other features and advantages of the invention will be evident from reading the following detailed description, which is intended to illustrate, but not limit, the invention.